田内 康

Using a mesh grid bias method for plasma parameter control, volume production of hydrogen negative ions H" is studied in pure hydrogen rf plasmas. Relationship between the extracted H" ion currents and plasma parameters is discussed. Both high and low electron temperature Tc plasmas are produced in the separated regions when the grid is negatively biased. In addition, with changing grid potential Vg, values of nc increase while Tc decrease in their values. The negative ion production depends strongly on the grid potential and related plasma conditions. It is also confirmed that grid bias method is more effective than the so-called magnetic filter method to optimize plasma parameters for H" production. Production of deuterium negative ions D" is also studied briefly. © 2009 American Institute of Physics.

This chapter discusses the varying magnetic field intensity of the magnetic field (MF), plasma parameter control in hydrogen (H2), deuterium (D2) plasmas, and its influence on H/D production. The relationship between H/D density distribution and plasma parameter control is discussed. The dependence of extracted H/D currents on H-/D- densities in the source is also discussed. To understand H/D negative ion formation mechanism and behavior of H/D ions in volume negative ion sources, axial distributions of H-/D densities in the source are measured directly by laser photo detachment method. H and D densities have different spatial distributions, respectively, corresponding to those different plasma parameter conditions. Plasma parameters are changed almost in the same manner by varying the magnetic field intensity of the MF. Axial distributions of plasma parameters across the MF affect electron detachment (ED) process more strongly than dissociative attachment (DA) process. © 2005 Elsevier Ltd. All rights reserved.